Thermoplastic recording process



United States Patent 3,441,947 THERMOPLASTIC RECORDING PROCESS UlrichSchmiedel, Hamburg, Germany, Louis Achille Meeussen and Paul MariaCassiers, Mortsel-Antwerp,

and Rene Maurice Hart, Wilrijk-Antwerp, Belgium;

said Meeussen, said Cassiers, and said Hart, assignors to GevaertPhoto-Producten N.V., Mortsel, Belgium, a

Belgian company No Drawing. Continuation-impart of application Ser. No.

110,342, May 16, 1961. This application Oct. 7, 1965,

Ser. No. 493,866 Claims priority, application Great Britain, May 17,1960,

17,452/ 60 Int. Cl. G01d /14, 15/12 U.S. Cl. 346-74 9 Claims Thisapplication is a continuation-in-part of application Ser. No. 110,342,filed May 16, 1961, and now abandoned.

This invention relates to novel methods for recording and reproducinginformation.

According to a recently proposed method (W. E. Glenn, Journal of AppliedPhysics, volume 30, pages 1870-1873, 1959), information is recorded inthe form of deformations or ripples in the surface of a thermoplastictape. The information can be detected optically by projecting lightthrough these ripples to form a visible image on a screen. The tapeconsists of a high melting base film coated with a metallic conductinglayer which is in turn coated with the low melting thermoplasticmaterial. By means of an electron gun, information can be written on thesurface of the thermoplastic layer in the form of a charge pattern. Uponheating the tape above the melting point of the thermoplastic material,electrostatic forces between the charge pattern and the metallic,conductive layer caused deformations or ripples in the tape surface.Cooling the tape below the melting point of the thermoplastic materialfreezes these deformations, thus yielding a permanent record of therecorded information. A modi- -fied Schlieren optical system is employedto project the recorded information on a screen. The tape may be erasedfor reuse by heating the film above its melting point for a period oftime suificient to allow the charge pattern to drain away and to allowthe surface tension of the thermoplastic layer to smooth out thedeformations.

Throughout the specification the phrase, thermoplastic recordingprocess, will be employed to indicate the process described.

The Glenn process suffers from the disadvantage that the employment ofan electron gun to record information requires the maintenance of vacuumconditions. This necessitates the employment of additional bulkierapparatus which results in a more expensive and less efficient process.

It is an object of the present invention to overcome this inherentdeficiency in the Glenn process.

It is a further object of the present invention to provide an eflicientmethod for the recordation and reproduction of information.

It is a further object of the present invention to provide aninformation recordation process which constitutes an improvement overthe Glenn process.

These and further objects are realized, according to the presentinvention, by effecting the thermoplastic recordation of information ona photoconductive, polymeric material.

The method according to the present invention may be described broadlyas follows.

Instead of the thermoplastic film material employed by Glenn, the methodof the present invention utilizes a low melting, thermoplastic,photoconductive, polymeric material. Thus, the tape consists of a highmelting base 3,441,947 Patented Apr. 29, 1969 ice film coated with athin, conductive layer which is in turn coated with a photoconductivepolymeric layer. The use of a photoconductive, polymeric materialenables simpler, more efficient recording apparatus than has beenheretofore possible in thermoplastic recording processes.

It is well known that the conductivity of a photoconductive material isincreased by exposure to visible electromagnetic radiation. Thischaracteristic of photoconductive materials enables recordation ofinformation in the form of charge patterns in these materials.

In the method according to the present invention, for example, a uniformelectrostatic charge is placed on the surface of the photoconductivelayer of the thermoplastic tape by exposure to a charging device, suchas a corona generating device. Upon exposure to a radiation image, thecharge in the exposed areas of the tape is dissipated by virtue of theselective increase in conductivity in these areas. The tape thencontains an image in the form of a charge pattern. The tape is thenfurther processed in the manner according to Glenn by first, heating thetape above the melting point of the photoconductive layer to allowdeformations or ripples to form in the surface of the tape; second,cooling the tape to freeze these ripples into a permanent record andthird, optically detecting the recorded information in a suitableprojection apparatus.

It is readily apparent, that the method of the present inventionconstitutes an improvement over the prior art process. Thus, the needfor bulky, expensive and inefficient vacuum equipment is eliminated. Themethod of the present invention merely involves simple charging andexposure operations which can be carried out with simple equipment underatmospheric pressure condition. The present method is therefore lessexpensive, more efiicient and less complicated than the prior artmethods.

Photoconductive polymeric materials useful in the process of the presentinvention include any macromolecular substance or any mixture ofmacromolecular substances which on exposure to radiation of suitablewavelength exhibits an increase in conductivity. The following classesof polymeric substances have been found to be especially useful:

A. Vinylpolymers and related compounds, i.e.,

(1) Vinyl polymers with acetal groups, such as, e.g.,

Po1y*(vinyl formal) Poly (vinyl acetal) Poly(vinyl butyral) (2) Vinylpolymers with unsaturated compounds in the side chain such as, e.g.,

=(a) Poly(vinyl cinnamate),

(b) Vinyl polymers and copolymers containing or consisting of recurrentunits of the following general formula:

wherein:

A represents a divalent radical such as NHCO, NHCONH or 0C0;

R represents a hydrogen atom or a substituent of the aromatic nucleussuch as methoxy group; and

R represents a hydrogen atom or a methyl group, such as, e.g.,

Poly (4-methacrylyloxy) -stilbene] Poly p- N'-vinylureido -stilbene]Poly [4-methoxy-4'- (N-acrylyl -aminostilbene] Copolymer of vinylacetate and p-(N-vinylureido)-stilbene,

(3) Vinyl polymers and copolymers containing a heterocyclic or anaromatic polycyclic nucleus in the side chain.

(a) Vinyl polymers and copolymers containing or consisting of recurrentunits of the following general formula:

mo A R H I -1 N wherein A represents a divalent radical such as NHCO,CH=N or NHCONH; Y represents an oxygen atom or a sulfur atom; and Rrepresents a hydrogen atom or a methyl group, such as, e.g.,

Poly[2-methyl-6-(N-acrylyl)-aminobenzoxazole], reaction product ofpolyacroleine and 2-methyl- 6-aminobenzoxazole, Poly [2-methyl-6-N'-vinylureido -benzoxazole]Poly(Z-methyl-6-acrylyl-aminobenzothiazole), Copolymer of vinylacetate,and 2-methyl-6-(N'- vinyl-ureido)-benzoxazole, Copolymer of styrene and2-methyl-6-(N'-vinylnreido)-benzoxazole, Copolymer of ethyl arcrylateand 2-methyl-6-(N- acrylamino)-benzothiazole, Poly[2 methyl 6 (N'-viny1)ureido benzothiazole], Copolymer of 2-methyl-6-(N'-vinyl)-ureido-benzothiazole and vinyl acetate, Copolymer of2-methyl-6-(N'-vinyl)-ureido-benzothiazole and ethyl acrylate. (b) Vinylpolymers and copolymers containing or consisting of recurrent units ofthe following general formula:

wherein:

A represents a divalent radical such as or a single bond;

Q and Q each represents a hydrogen atom, a methyl radical, a nitrogroup, a phenyl group, a substituted phenyl group, or form together theatoms necessary to close a ring;

R represents a hydrogen atom or a methyl group;

X=N or a methine group; and

:8, O, imino group, isopropylidene group, dimethine group or asubstituted dimethine group, such as, e.g.,

Poly[2 (4'-acrylyloxy-phenyl) 4(4"-dimethylaminophenyl)-5-phenyl-imidazole],

Poly[2 (4'-methacrylyloxyphenyl) 4 (4"-dimethylaminophenyl-5-phenylimidazole] Poly[2 (2'-N-acrylylaminophenyl) 4,5diphenylimidazole],

4 Poly[l (2'-methacrylyl-oxyethyl) 2,4,5 triphenylimidazole], Poly(2vinyl 3 isopropylidene 5 dimethylpyrroline), 5 Reaction product ofpolyacrolein and 2-aminothiazole, Reaction product of polyacrolein andZ-amino-S- nitrothiazole, Reaction product of polyvinylamine and4-pyridine aldehyde,

Reaction product of polyvinylamine and 2-quinoline aldehyde,

Poly[p-(2-quinoline-4-carboxylic acid) styrene],

Copolymer of styrene and 2-(2'-N'-vinylureido)-phenyl-4,S-diphenylimidazole,

Poly(2-vinyl benzoxazole),

Poly(2-vinyl benzothiazole),

Poly[2 (4'-acrylyloxyphenyl) 4,5 diphenylimidazole],

Poly[2 (2'-acrylyloxynaphthyl) 4 phenyl 5- (4-dimethylaminophenyl-imidazole] (c) Vinyl polymers consisting of or containing recurringunits of the following general formula:

wherein:

A represents a single bond or CH CH OCO; Q Q and Q each represents ahydrogen atom or a phenyl nucleus; and R represents a hydrogen atom or amethyl group, such 4 as, e.g.,

Polyvinyl imidazole, Poly[l (2'-methacrylyloxyethyl) 2,4,5 triphenylimidazole] (d) Vinyl polymers consisting of or containing recuring units of the following general formula:

A represents N=CH or CH=N;

Q and Q together represent the atoms necessary to close an aromaticnucleus;

Y represents a single bond, 3. sulphur atom or a carbonyl Z represents acarbonyl group or a nitrogen atom substituted by a lower alkyl radical;and R represents a hydrogen atom or a methyl group, such as, e.g.,

Reaction product of polyvinyl amine andN-methylphenothiazine-Z-aldehyde, Reaction product of polyvinyl amineand N-ethylcarbazole-Z-aldehyde, Reaction product of polyacrolein andl-aminoanthraquinone, Reaction product of polyacrolein and3-arninocarbazole. (f) Other vinyl polymers and copolymers containing aheterocyclic or aromatic polycyclic nucleus in the side chain:

Poly [2- 1-acrylyloxyethyl -fiuorene] Poly [4-vinylphenyl-2-N-ethylcarbazyl -carbinol] Poly[ 1,3-diphenyl-5- (4-acr1yloxyphenyl-2-pyrazoline] (4) Vinyl polymers containing a diarylmethane group inthe side chain, such as poly(p-vinyl-p'-dimethylaminodiphenyl-carbinol)(5 Vinyl polymers and copolymers such as Terpolymer of vinyl chloride,vinyl acetate and vinyl alcohol,

Terpolymer of vinyl chloride, vinyl acetate and maleic anhydride,

Nitrated terpolymer (vinyl acetate/styrene/maleic anhydride),

Copolymer of vinyl acetate and mono-n-decylinaleate.

(6) Vinyl polymers and copolymers containing or consisting of recurrentunits of the following general formula:

A represents a single bond, or a divalent organic radical such as, e.g.,

-CH2-, CH CH -COO-, -CH -CH CH O-CO-, -CH2CH2-COC6H4, -CH -C H R and Reach represents a hydrogen atom or a lower alkyl radical such as, e.g.,a methyl radical; Z represents a sulphur atom or a single bond; Zrepresents a rnethine group or a nitrogen atom; Q and Q togetherrepresent the atoms necessary to complete an aromatic nucleus; and Q andQ together represent the atoms necessary to complete an aromaticnucleus, such as, e.g.,

Poly (9-methacrylyloxyf1uorene) Poly(N-acrylylphenothiazine Poly [NZ-acrylyloxy-ethyl -phenothiazine] Poly(N-allyl carbazole) Poly [N-(Z-acrylyloxypropyl -phenothiazine] Poly(N-Z-acrylyloxy-2-methyl-N-ethylcarbazole), Poly [N (Z-pwinylbenzoylyethyl -carbazole] Poly(N-propenylcarbazole), Poly(N-vinyl carbazole) Poly [N- (Z-methacrylyloxypropyl-carb azole] Poly [N- acrylyl -carb azole] Poly [4-vinyl-a- (N-carbazyl-toluene] M01 percent of N-vinyl carbazole Copolymer of N-vinylcarbazole and vinylidene Copolymer of N-vinyl carbazole and vinylacetate 88.6 Copolymer of N-vinyl carbazole and isopropenyl acetate Molpercent of N-vinyl carbazole Copolymer of N-vinyl carbazole andvinylstearate 37.5 Copolymer of N-vinyl carbazole and methyl acrylate67.6 Copolymer of N-vinyl carbazole and methyl acrylate 4l Graftcopolymer of N-vinyl carbazole and poly(ethyl acrylate) 90.3 Emulsionpolymer of N-vinyl carbazole and ethyl acrylate 94.5 Copolymer ofN-vinyl carbazole and m-butyl acrylate 58.3 Copolymer of N-vinylcarbazole and Z-ethyl-hexyl acrylate 51.6 Copolymer of N-vinyl carbazoleand acrylyloxyethyl diethylamine 76.6 Copolymer of N-vinyl carbazole andvinylcinnamate 92.5 Copolymer of N-vinyl carbazole and ethylmethacrylate62.7 Copolymer of N-vinyl carbazole and isobutyl methacrylate 51.8Copolymer of N-vinyl carbazole and lauryl methacrylate 77.4 Copolymer ofN-vinyl carbazole and methacrylyloxyethyl diethylamine 9.7 Copolymer ofN-vinyl carbazole and acrylonitrile 88 Graft copolymer of N-vinylcarbazole and butyraldehyde acetal of polyvinyl alcohol 59 Copolymer ofN-vinyl carbazole and di(2-chloroethy1)-vinyl phosphonate 82.4 Copolymerof N-vinyl carbazole and styrene 49 Graft copolymer of N-vinyl carbazoleand polystyrene 27.3

Copolymer of N-vinyl carbazole and vinylnaphthalene 47.1 Copolymer ofN-vinyl carbazole and anthracene-(9,

10) Copolymer of N-vinyl carbazole and 2-vinyl pyridine Copolymer ofN-vinyl carbazole and 4-vinyl pyridine Copolymer of N-vinyl carbazoleand N-vinyl pyrrolidone Terpolymer of N-vinyl carbazole, acrylonitrileand styrene Graft copolymer of a terpolymer of vinyl chloride,

vinyl acetate and vinyl alcohol with N-vinyl carbazole Graft copolymerof a terpolymer of vinyl chloride, vinyl acetate and maleic anhydridewith N-vinyl carbazole 55.1

(7) Vinyl polymers and copolymers containing or con sisting of recurrentunits of the following general formula:

A represents an aromatic nucleus such as, e.g., a benzene nucleus or aheterocyclic nucleus such as a carbazole nucleus;

B represents an aromatic nucleus such as e.g., a benzene, a naphthaleneor anthracene nucleus, or a heterocyclic nucleus such as, e.g., acarbazole, phenothiazine or quinoline nucleus;

R represents a hydrogen atom or a lower alkyl radical such as, e.g., amethyl radical; and

n and m each represents a positive integer from 1 to 2,

such as, e.g.,

Poly(vinyl benzal acetophenone),

Poly(vinyl cinnamal acetophenone) Poly(vinyl anisal acetophenone),

Reaction product of poly(vinyl acetophenone),

and p-dimethylaminocinnamaldehyde,

Reaction product of poly(viny1 acetophenone) and l-naphthaldehyde,

Reaction product of p0ly(vinyl acetophenone) and 9-anthraldehyde,

(8) Polymers and copolymers obtained by reacting halogenated polymers orcopolymers with compounds containing an aromatic nucleus or by reactingone or more halogenated monomers with polymeric substances containingaromatic groups, such as e.g.

Reaction product of polyvinyl chloride and anthracene,

Reaction product of polyvinyl chloride and fluorene,

Reaction product of polyvinyl chloride and naphthalene,

Reaction product of polyvinyl chloride and toluene,

Reaction product of polyvinyl chloride and N-methylphenothiazine,

Reaction product of polyvinyl chloride and carbazole,

Reaction product of polyvinyl chloride and phenothiazine,

Reaction product of polyvinyl chloride and N-ethyl carbazole,

Reaction product of polyvinyl chloride and phenoxathine,

Reaction product of polyvinyl chloride and acridine,

Reaction product of polyvinyl chloride and lophine,

Reaction product of after-chlorinated polyvinyl chloride and anthracene,

Reaction product of chlorinated natural rubber and anthracene,

Reaction product of after-chlorinated polyvinyl chloride andnaphthalene,

Reaction product of chlorinated natural rubber and naphthalene,

Reaction product of polyvinyl benzylbromide and N-ethyl carbazole,

Reaction product of the copolymer of vinyl chloride and styrene withnaphthalene. B. Polyesters, such as, e.g.,

Polyester of 2,2-di(4-hydroxyphenyl)-propane and isophthalic acid,

Polyester of benzene-1,3-disulphonic acid and 2,2-di(4- hydroxyphenyl-prop ane,

Polyester of diphenyl-p,p'-disulphonic acid and 2,2-(4- hydroxyphenyl-propane,

Polyester of 2,2-di(3-methyl-4-hydroxyphenyl)-propane and stilbenediscarboxylic acid,

Polyester of 4,4'-dicarboxydiphenyl and neopentyl glycol,

Polyester of isophthalic acid and di(4-hydroxyphenyl)-methylphenylmethane,

Polyester of di(4-hydroxyphenyl)-phenylt1nethane andbenzophenon-4,4'-dicarboxylic acid,

Polyester of diphenyl ether-p,p-disulphonic acid and 2,2-

di (4-hydroxyphenyl -prop ane,

Polyester of diphenyl ether-4,4'-disulphonic acid and di(4-hydroxyphenyl) -phenylm ethane,

Polyester of diphenyl-4,4'-disulphonic acid and 4,4'-di(4-hydroxyphenyl) methylphenylmenthane,

Polyester of diphenyl-4,4'-disulphonic acid and 2,2-di(4- hydroxyphenyl)-butane,

Polyester of diphenyl-p,p'-disulphonic acid and 3,3'-di(4-hydroxyphenyl) -p entane,

Polyester of l,3-diphenylpropane-p,p-dicarboxylic acid and 2,2-di(4-hydroxyphenyl -prop ane,

Polyester of diphenyl-p,p'-disulphonic acid and 2,2-di(3-methyl-4-hydroxyphenyl)-propane,

Polyester of diphenyl-p,p-disulphonic acid and 2,2-di(4-hydroxy-3,S-dichlorophenyl) -propane,

Polyester of diphenyl-p,p'-disulphonic acid and 2,2-di(p hydroxyphenyl)-4-methy1-pentane,

Polyester of diphenyl-p,p'-disulphonic acid and l,1-di(3-methyl-4-hydroxyphenyl) -cyclohexane,

Copolyester of 2,2 di(4-hydroxyphenyl)-propane and isophthalic acid withterephthalic acid,

Copolyester of diphenyl ether-p,p'-dicarboxylic acid withdiphenyl-p,p-disulphonic acid with 2,2-di(4-hydroxyphenyl) -prop ane,

Copolyester of terephthalic acid and diphenyl-p,p'-disulphonic acid with2,2-di(4-hydroxyphenyl)-propane, Copolyester ofdiphenyl-p,p'-disulph0nic acid and diphenyl ether-p,p'-disulphonic acidwith 2,2-di(4-hydroxyphenyl)-propane and 2,2-di(4-hydroxyphenyl)-butane,

Copolyester of diphenyl-p,p-disulphonic acid and terephthalic acid with2,2-di(3-methyl-4-ihydroxyphenyl)- propane,

Copolyester of terephthalic acid and isophthalic acid with2,2-di(4-hydroxy-3,5-dichloro phenyl)-propane,

Copolyester of 2,2-di(4-hydroxy-3,S-dibromophenyl)-propane and2,2-di(4-hydroxyphenyl)-propane with isophthalic acid.

Copolyester of fluorene-3,6-disulphonic acid and diphenylp,p-disulphonicacid with 2,2-di(4-hydroxyphenyl)- propane.

C. Cellulose-derivatives such as, e.g.,Cellulose-aceto-N-phenylcarbamate, Cellulose-acetocinnamate.

The thermoplastic photoconductive polymers may be employed incombination with substances increasing their sensitivity, suchsubstances are, e.g., mentioned in the British patent specifications964,871-964,875 and 964,877.

The tape may consist solely of self-supported photoconductive polymericmaterial or it may consist of the photoconductive polymeric materialcoated upon a high melting base film such as one sold under thetrademark Mylar or Cronar, for example. In either case, it is necessarythat the photoconductive polymeric layer be in intimate surface contactwith a conductive backing. Any metallic or similar conductor, such ascopper or aluminium for example, may be employed. Should the tapecomprise a self-supporting photoconductive polymeric material, itsthickness should be sufiicient to allow heating of the surface on whichinformation is recorded only to a fraction of the thickness, so that thetape will remain in a selfsupporting state. Unually tapes of a thicknessof 10 to p. will suffice.

Recordation of information can be achieved simply, economically andefiiciently by any method involving exposure of the photoconductivematerial to a pattern of electro-magnetic radiation rendering thepolymer conductive and by bringing about a charge condition of theunexposed areas. 'For example, the recording medium may be uniformlycharged by passing thereover a corona generating device. Either apositive or negative electrostatic charge may be laid upon the film.Subsequently, the charged film is image-wise exposed to electromagneticradiation of suitable wavelength. The radiation struck areas of thephotoconductor, being rendered conductive thereby, charge is carriedoil. The unexposed areas of the film remain charged.

Alternatively, the photoconductive film may first be exposed image-wiseto electromagnetic radiation, thus rendering the light struck areasconductive and subsequently, uniformly charged with a corona generatingdevice. No charge will be laid down on the conductive, radiation struckareas of the film and an image comparable to that produced by the methoddescribed above will occur.

The advantages of such a system over that described by Glenn areobvious. There is no need for bulky, expensive and inefficient vacuumapparatus or an electron gun for producing the desired image. Only asimple charge generating device and a source of electromagneticradiation are necessary. Furthermore, the nature of the photoconductivepolymeric material makes it possible to render the recording mediumcompletely self-supporting without need for a base material.

Development of the recorded image and its reproduction may beaccomplished in the same manner as that disclosed by Glenn. By merelyheating the photoconductive polymer above its melting point,electrostatic attraction between charges on the film and its conductivebacking will cause deformations or ripples in its surface. Cooling themedium below the melting point, will freeze these ripples into apermanent record.

Reproduction of the recorded image may be accomplished by means of anyconventional optical projection system. For example, a system based uponthe principles of phase diffraction grating whereby visible light,diffracted by the ripples in the photoconductive medium is permitted toshine upon a screen while light which passes through smooth, nondeformedareas of the film is not permitted to shine upon the screen, a visiblereproduction of the recorded information is produced. For optimumresults, the recorded electrostatic latent image in the photoconductivelayer should be built up line-wise by exposure, e.g., to a light spot ofa flying spot scanner. Such a method will yield a ripple image adaptedfor reproduction in a phase diffraction system. It is to be understood,however, that any suitable and conventional optical projection systemmay be employed to reproduce the ripple image.

EXAMPLE On an electrically conducting metallic backing is cast aphotoconductive thermoplastic layer of the following composition:

Polypropenyl carbazole g 8 Ester gum g 2 Methylene chloride cc 100 Thedried photoconductive layer has a thickness of 1.5 to 2 microns.

The material is charged by means of a corona generating device and alatent electrostatic record of information is created by selectivelycarrying otf electric charge from the material using a light spot(flying spot scanner). The material is then heated to the melting pointof the polymeric material and after the deformations have set inaccording to the charge pattern, the material is cooled to freeze thedeformations.

Reproduction of the image is accomplished by employing projectionapparatus such as that described by W. E. Glenn. The material is erasedby melting the polymeric material above its melting point while exposingit to light. Subsequent, recordations on the erased tape by this samedescribed method, produced excellent images.

What we claim is:

1. A process for recording optical information on a deformable layer inthe form of a relief pattern, which comprises electrostatically charginga layer of a thermoplastic photoconductive polymeric layer superimposedupon a layer of conductive material before or after said layer issubjected to electromagnetic radiation to which said photoconductivelayer is sensitive in a pattern according to said information to berecorded so as to produce on said layer an electrostatic charge patternin accordance with the information to be recorded, heating said materialto a degree suflicient to soften at least the surface layer of thepolymeric said layer whereby said softened surface layer is deformedphysically under the influence of the electrostatic forces existingbetween the charge pattern at the surface of said photoconductive layerand said conductive layer, and cooling said heated layer to fix thedeformations therein.

2. The process of claim 1 wherein said polymeric layer is uniformlycharged and subsequently exposed to said electromagnetic radiationimage.

3. The process of claim 1 wherein said polymeric layer is exposed tosaid electromagnetic radiation image and subsequently uniformly charged.

4. The process of claim 1 wherein said. polymeric layer is in the formof a tape.

5. The process of claim 4 wherein said tape comprises of high meltingbase layer coated with said polymeric layer.

6. The process of claim 4 wherein said tape comprises of self-supportinglayer of said photopolymer.

7. The process of claim 1 wherein said conductor is in the form of acoating on said photopolymer.

8. The process of claim 1 wherein said recorded image is built upline-wise by means of a light spot of a flying spot scanner.

9. The process of claim 1 wherein polymeric layer additionally containsa radiation sensitive substance.

References Cited UNITED STATES PATENTS 2,896,507 7/1959 Mast 88-613,055,006 9/1962 Dreyfoos 34674 3,284,196 11/1966 MaZZa 96--l.1

TERRELL W. FEARS, Primary Examiner.

US. Cl. X.R.

1. A PROCESS FOR RECORDING OPTICAL INFORMATION ON A DEFORMABLE LAYER INTHE FORM OF A RELIEF PATTERN, WHICH COMPRISES ELECTROSTATICALLY CHARGINGA LAYER OF A THERMOPLASTIC PHOTOCONDUCTIVE POLYMERIC LAYER SUPERIMPOSEDUPON A LAYER OF CONDUCTIVE MATERIAL BEFORE OR AFTER SAID LAYER ISSUBJECTED TO ELECTROMAGNETIC RADIATION TO WHICH SAID PHOTOCONDUCTIVELAYER IS SENSITIVE IN A PATTERN ACCORDING TO SAID INFORMATION TO BERECORDED SO AS TO PRODUCE ON SAID LAYER AN ELECTROSTATIC CHARGE PATTERNIN ACCORDANCE WITH THE INFORMATION TO BE RECORDED, HEATING SAID MATERIALTO A DEGREE SUFFICIENT TO SOFTEN AT LEAST THE SURFACE LAYER OF THEPOLYMERIC SAID LAYER WHEREBY SAID SOFTENED SURFACE LAYER IS DEFORMEDPHYSICALLY UNDER THE INFLUENCE OF THE ELECTROSTATIC FORCES EXISTINGBETWEEN THE CHARGE PATTERN AT THE SURFACE OF SAID PHOTOCONDUCTIVE LAYERAND SAID CONDUCTIVE LAYER, AND COOLING SAID HEATED LAYER TO FIX THEDEFORMATIONS THEREIN.